One who accompanies or is in company with another for a longer or shorter period, either from choice or casually; one who is much in the company of, or is associated with, another or others; an associate; a comrade; a consort; a partner.

A skylight on an upper deck with frames and sashes of various shapes, to admit light to a cabin or lower deck.

(b)

A wooden hood or penthouse covering the companion way; a companion hatch.

Companion hatchNaut., a wooden porch over the entrance or staircase of the cabin. -- Companion ladderNaut., the ladder by which officers ascend to, or descend from, the quarter-deck. Totten. -- Companion wayNaut., a staircase leading to the cabin. -- Knights companions, in certain honorary orders, the members of the lowest grades as distinguished from knights commanders, knights grand cross, and the like.